TXL's inhibitory effects on cellular growth and apoptosis in HT-29 cells. (A) Apoptosis in HT-29 after TXL treatment for 48 hours was determined by staining the cell with DAPI. Apoptotic cell exhibiting characteristic chromatin condensation were observed by fluorescence microscopy. (B) Cell proliferation was assessed after 24 and 48 hours with the MTT assay as described in Methods. Results (optical densities) are expressed as mean and standard deviation (n = 3). The experiment was repeated three times with similar results. CTL: control.